Problem: What is the greatest common factor of $5$ and $7$ ? Another way to say this is: $\operatorname{gcf}(5, 7) = {?}$
Answer: The greatest common factor is the largest number that is a factor of both $5$ and $7$ The factors of $5$ are $1$ and $5$ The factors of $7$ are $1$ and $7$ Thus, the greatest common factor of $5$ and $7$ is $1$. $\operatorname{gcf}(5, 7) = 1$